Realme Buds Air Pro BLUETOOTH PAIRING
Open the upper cover of the charging case, place the earbuds inside, then press and hold the multi-function button for 3 seconds to switch the earbuds to Bluetooth pairing mode.*When using the product for the first time, open the upper cover of the charging case with the earbuds inside to automatically switch to Bluetooth pairing mode.

The indicator light of the charging case will flash green.

Search for “realme Buds Air Pro” on Bluetooth to complete the pairing process.
*After the earbuds are paired, they will automatically connect when the charging case is opened.
*After the earbuds are paired, they will automatically connect when the charging case is opened.

Source: https://manuals.plus/realme/rma210-buds-air-pro-earbuds-manual#ixzz7Wj9y5QsL